1. Field of the Invention
The present invention relates to an endoscopic vision system and a related method of viewing a body lumen.
2. Background of the Related Art
Millions of endoluminal procedures are performed each year. An endoluminal procedure takes place within a tube, or lumen, of the human body, such as a vascular, gastrointestinal, or air exchange lumen, and generally involves the diagnosis and/or treatment of diseases. Endoluminal procedures generally involve use of an endoscope, a rigid or flexible tube which can be introduced into the human body through the entrance to a lumen of the body, such as the mouth or rectum. Alternatively, an endoscope may be inserted into the human body through an incision made by a surgeon. The endoscope allows the surgeon to view the patient and an intended surgical site internally without the surgeon being in a direct line of sight with the object or area being viewed. The endoscope provides one or more open, working channels, or pathways, between a desired surgical site and the surgeon. An endoscope may carry, for example, one or more lights, visioning systems, and other tools, such as diagnostic and treatment devices that extend from a proximal end near by the surgeon, through the working channel, and to the distal end at a surgical site. The size of the endoscope used may vary, depending on the particular lumen of the patient and the size and number of instruments which need to be introduced to the surgical site.
Endoscopes typically are manually inserted into the patient by the surgeon and manually steered or positioned by the surgeon or nurse by pushing the endoscope through the body until the endoscope is properly positioned. Dependent upon the size and flexibility of the endoscope used, forcing the endoscope into a lumen of the patient may traumatize the surrounding tissues. Thus, the ability to visualize the area into which the endoscope is being inserted is important. To view the area, an endoscope may communicate with a monitor to display the field of view. However, lack of an adequate field of vision, poor resolution, and poor illumination are problems in existing endoscopic visioning systems which make it difficult for a surgeon to view the surgical area and accurately position an endoscope.
FIGS. 1 and 2 illustrate an embodiment of a conventional endoscope. It includes an insertion tube, a lumen or working channel within the insertion tube, a light source and a vision chip. Such an endoscope has several limitations. For example, the opening to the working channel, the light source, and the vision chip are each restricted to, for example, a couple of millimeters in diameter. This compromises performance of the visioning system and increases costs for components of the system due to the need to miniaturize the components. The limited space available on a working end of a conventional endoscope restricts the size of the visioning system. Such visioning elements also take away needed space for the working channel(s) of the endoscope-limiting the size and number of the tools which can pass through the working channel.
Larger, more rigid endoscopes can support larger, more powerful light sources for better illumination and larger vision chips for better resolution. Such endoscopes, however, lack flexibility, making it more difficult to maneuver the endoscope within the body. Smaller, articulating endoscopes are much more flexible but are relatively small in diameter, and thus lack the size necessary to support larger illumination and resolution elements.
In addition, such a system is only forward-looking, and has a relatively narrow field of vision, with a viewing angle of, for example, about 120 degrees, as shown in FIG. 2. This makes it extremely difficult for a surgeon to view the region where the endoscope enters the body lumen. Very flexible endoscopes may perform what is known as a “scope-retrograde” maneuver, in which the endoscope bends back upon itself to allow the user to visualize the endoscope's point of entry. Such endoscopes are expensive, require expertise on the part of the operator, and require space within the body lumen to perform such a maneuver.
In light of the difficulty in positioning devices introduced into the human body through endoscopes, the difficulty in maximizing working channel space, and the difficulty of providing adequate illumination, resolution, and field of vision in existing visioning systems for endoscopes, there is a need for a method and device which solve these problems.